MX2007002578A - Energy-saving led-based lighting device. - Google Patents

Abstract

The invention relates to an energy-saving lighting device formed by light-emitting diodes (LEDs) which use a scanning technique in order to reduce the amount of energy required for lighting. Said scanning technique is performed by an efficient circuit which determines the lighting times and sequence of each LED or group of LEDs. The invention is not restricted to the use of LEDs, but can also be used to control other types of elements which can be sequenced without altering the useful life or operation thereof. This case involves the use of speeds that LEDs can withstand that are beyond that of the human eye, at which each LED or group of LEDs turns on and off at a frequency imperceptible to the human eye. The invention also relates to voltage reduction solutions using electronic means and current rectification using the LEDs that are also used for lighting.

Description

Lighting Device with Energy Saving based on LEDs DESCRIPTION OBJECT OF THE INVENTION The invention described herein is a lighting device whose source of illumination is constituted by light emitting diodes (LEDs). This lighting device can be connected to any socket on which a conventional bulb is connected and also has a variant, which consists of being able to connect to batteries powered by photovoltaic cells, even directly to photovoltaic cells or any direct current voltage source. The lighting device contains a network of LEDs distributed in arrays that can be linear, matrix, circular or other types of uniform or non-uniform arrangements. These LEDs are connected individually or in groups according to the number of LEDs that have been arranged in the device and the need for lighting required by the user. The main objective of the present invention is to reduce the consumption of electrical energy necessary for lighting and produce efficient lighting. This is achieved because of the set of LEDs, only one or a group of LEDs is turned on at the same time. This is carried out using the technique called by our research group as "swept" by which the LEDs are turned on and off consecutively, either one by one or group by group. A group is composed of two or more LEDs. The turning on and off is done at a frequency such that the on and off is imperceptible to the human eye, resulting in the human eye perceiving the lighting as if the whole set of LEDs was always on. Consequently, the lighting device appears to have always lit all its LEDs but the energy consumption is proportional to the number of LEDs lit and as a result a lower energy consumption is obtained.

BACKGROUND The present invention represents a technology for generating lighting with low energy consumption. More particularly, the invention disclosed herein is a lighting device composed of a network of LEDs. It is generally known that the current resources for generating electricity in the world are very limited, and therefore, it is vital to consume the least amount of energy possible, both for economic reasons, and for environmental conservation. And with the purpose of providing a solution, first of all to the problem of lighting, different lighting devices have been developed, among them we can mention conventional devices such as, for example, the incandescent light bulb that is described in the publication: WO / 2006/070190, which It is low in price, but very inefficient and fragile. After trying to reduce the high energy consumption, other devices have been developed, such as the one described in the publication: WO / 2006/006097 which describes a compact fluorescent lamp, which with a similar principle to its predecessors uses inert gas which, in the presence of electricity , it lights up; in general, this lighting device is more efficient than the incandescent bulb because it allows energy saving, however, the lamp or fluorescent tube requires ballasts and lighters which makes them more complicated and expensive, in addition to being generally bulky and fragile. Another variety is the thrifty focus which is known as high discharge intensity (H1D), such as that described in US Patent 4,431,942; These bulbs achieve efficiencies superior to those of fluorescent bulbs, although they have the disadvantage of a high level of ultraviolet light emission, so they require special filters. They also have the disadvantage of requiring ballasts and lighting aids similar to those of fluorescent lamps as described in US Pat. No. 5,339,005. Another disadvantage of HID lamps is that they require correction of the power factor as mentioned in the US patent 7, 078,870. HID lamps are also prone to their noise level being raised by acoustic resonance, which is why special measures such as those described in patent US 7084578 are required. The use of HID lamps has been spread in automotive sources, as well as in places where the lighting of large areas with high intensity of lighting is required. One more variety, focused on saving electricity, are light-emitting diodes (LEDs); the LEDs represent an advance of the technology, because they consume less energy than the incandescent bulbs since they generate less heat but; in the case of white light they still do not achieve the level of efficiency of the fluorescent bulbs. Although its development is expected to achieve competitive efficiency levels. A characteristic of a lighting device with LEDs, is that these being light emitting diodes can be used as part of the electronics required for the rectification of the current, thus decreasing the total cost of this. As shown in the patent application MXNL05000079, where the LEDs are used to rectify the alternating current of a socket of the electric network. In the present invention this concept is also used for said purpose, however this invention differs with the patent XNL05000079 because in said patent the set of LEDs turn on and off all at frequencies of 120Hz (60Hz x 2 because the diode bridge change the frequency). In the present invention, there is a digital logic stage, which allows to provide special control over portions of the total of LEDs, which results in greater energy savings. In the present invention, the LEDs are used with a double purpose, the first of them as lighting devices and additionally, for the rectification of the alternating current, with which impact is achieved in the reduction of the cost. Next we will make a tour of patents related to lighting devices based on LEDs, such as US 6,016,038 claiming an apparatus for generating light, consisting of one or more LEDs, a terminal for connection to a source and an addressable processor to generate signals by means of which the intensity or color of the LEDs can be changed; another example is patent US 6, 149, 283 which consists of a focus consisting of a line of LEDs of blue, red, green, and are configured in such a way that the resulting light is white and can be connected as any focus conventional, however its objective is limited to lighting without considering the cost reduction. On the other hand, the patent US 6,227,679 calls for an LED spotlight designed for lighting in general and of various types for example, decorative lamp, and traffic lights among other applications; this focus comprises a conical base with two circular openings, the first being of greater diameter than the second; a flat disk inserted in the first opening, where the circuitry and the LEDs are located, and a circuitry designed to provide current to the LEDs. This patent focuses on lighting but not in a special configuration such as the one we present and is the subject of this invention. Patent US 6,268,801 calls for a method for adjusting a traffic light by replacing the conventional focus used with a module containing light-emitting diodes, a power source connected to the LEDs and cables that connect the power source to a thread for spotlights, however, they do not use the LEDs for rectification nor show an array of LEDs, as in the present application, which are arranged in the form of a network. After mentioning some patents that describe LED-based lighting systems, we will focus on patents that reflect the current state of the art in relation to energy saving based on LEDs and that could be compared to the invention that is the subject of this application. US Pat. No. 5,850,126 presents a conventional shaped screw focus formed by LEDs. The LEDs turn on and off frequently and handle currents higher than they support. This concept turns on and off all LEDs and they remain a fraction of the time turned off than on, because the pulses that turn them on are less than those that keep them off. Compared this focus, with the device of the application presented here, we can describe as an advantage that the LEDs are controlled in such a way that we control the amount of LEDs turned off and on, in such a way that the lighting is maintained with the least number of LEDs lit and that this is imperceptible to the human eye, generating with this a lower consumption of energy. Patent US 6,160,354 controls interconnected LEDs as in a network, whose configuration and purpose are not lighting.

In addition to these patents, there is the concept known as PWM, (pulse width modulation of its acronym in English) for handling LEDs, however the use of this concept is for intensity effects and does not represent much energy savings given the approach you have. All these patents and applications present an overview of the current state of the art. However, in the aforementioned patent documents, they focus on using LEDs as an alternative source of lighting, but efforts are not focused on finding efficient ways to use the LEDs to save electricity. The present invention is based on a design that allows efficient use of the LEDs, without significant losses in lighting, thus achieving an even more substantial saving of electrical energy that can be more than 80% of the total consumption of the LEDs.

DETAILED DESCRIPTION OF THE INVENTION BRIEF DESCRIPTION OF THE FIGURES Figure 1: Exterior Focus Concept Figure 2: Block diagram of the lighting device in its Alternate Current (AC) variant. Figure 3: Block diagram of the lighting device in its Direct Current (CD) variant. Figure 4: Schematic diagram of the LED network. Figure 5: Schematic diagram of LED driver. Figure 6: Complete schematic diagram of the device without Zener diodes.

Figure 7: Complete schematic diagram of the device with Zener diodes. Figure 8: Rectifier with simple full wave bridge. Figure 9: Schematic of simple rectification. Figure 10: Schematic of rectification with parallel bridges. Figure 1 1: CD-CD converter.

DESCRIPTION OF THE INVENTION The invention described below is composed of several parts, first we will describe the external concept of the focus that is in the form of a conventional focus as shown in Figure 1, as seen, the thread of a conventional focus (1), this allows you to connect to a conventional socket. The bulb contains the necessary electronics to control the sequential ignition (sweep) of the LEDs as well as to provide the necessary voltage for its operation. The electronic circuits are located in its base (2) and inside the cube (3) the printed circuits (PCBs) with LEDs are located. This invention has the versatility that the lighting device can work both in Alternating Current (AC) and with Direct Current (DC), that is, it can be connected to the residential, commercial and / or industrial electrical network or to a power source direct, like a battery of the commercial type. Figure 2 shows a block diagram of the elements of the lighting device in the CA variant. Said variant has an AC rectification part (4) obtaining from the CD-CD converter (5) the voltage VDD to feed the network of LEDs (6) and the voltage VCC to feed the controller (7). However, if it is desired that the focus work with a CD source, AC rectification is not used, which results in the block diagram of the lighting device in its CD variant shown in Figure 3 in the that only the CD-CD converter (8) is required to produce the VDD and VCC voltages where these voltages feed the network of LEDs (9) and controller (10), respectively. The advantage of using a CD source is that it is possible to couple the circuit to an alternative energy source such as solar, wind, among others. One of the novelties of the present invention is described in Figure 4 where an example of a preferred arrangement of LEDs forming a network with a configuration similar to that of a Cartesian plane having columns and rows of LEDs can be seen as an example. In Figure 4 the rows are numbered from Yl to Yn (1 1) and the columns from XI to Xm (12). It is important to mention that each column (XI to Xm) has its own transistor (13) (in case of using a BJT, NPN) which has at its base a resistance RB (14), in its emitter it is connected to GND or reference and in its collector is a resistor Re (15). In addition, each row (And the Yn) also has its own transistor (16) (in case of using a BJT or bipolar junction transistor, PNP) which has a resistance RB (14) in its base, in its emitter it is connects to VDD and its collector connects to a number of LEDs equal to the number of columns that can vary from "1" to "m". In this Figure 4 the interconnection of the LEDs is seen, where the columns, Xi are interleaved with the rows, Yi, the resistance Re (15) fixes the current passing through the LED. It is important to emphasize that the model, family and characteristics of the transistors are not definitive or specific for the operation of the circuit. To facilitate the explanation of the controller circuit (sweep) an example will be set by setting both "n" and "m" in 4, that is, an arrangement of 4 LEDs is explained by 4 LEDs, giving a total in the proposed network of 16 LEDs .For the addressing and selection of the LEDs, the corresponding coordinate is activated through the controller described in Figure 5. In the specific case of 16 LEDs, these are selected through an account generated by a 4-bit binary counter. With these four bits it is possible to address the 16 LEDs since the LEDs are located as "rows" and "columns". For example, activating Y4 and X4 at the same time will only turn on the LED in the upper right corner. If Y4 and X3 are the activated positions, only the LED that precedes it will turn on. Activating only one column and one row transistor will only light one LED at a time. These transistors in this example are activated with the controller of Figure 5. Their function is to select only one row and one column at a time and after a certain time select another row-column pair until completing the whole "n per m", 4 for 4 for the example, and then restart your account. For the case of the example with 4-bit rows and columns this controller is preferably implemented by means of a binary counter (17) connected to two decoders (18 and 19) as shown in figure 5, the specific components for the example of 16 bits are specified later. The decoder (19) used to select the columns (XI to Xm); it must have its negated outputs with an inverter to perform the appropriate control over the NPN transistor in the interconnection between the LED network and the controller. In addition there is another decoder (18) for the rows, which is connected directly to the base of the PNP transistor, that is, they do not need to be inverted. In this particular case, the sweep sequence first turns on LED by LED of the first row (Y l), and when it ends, it does the same in the second row (Y2) and so on until it reaches the last row Yn (Y4 for the example) with the last column Xm (X4 for the example) and start again. However, the scanning sequence can be adapted to different requirements, the ignition can be carried out in any desired order or it can be produced randomly. A binary counter provides accounts that reach a power of 2, for example 4, 8, 16, 32, and so on doubling. For this circuit a counter is used that can generate an account that is equal to or greater than the number of LEDs. The design of the circuit is expandable to a greater number of rows and columns (n per m), here only a small one of 16 bits is shown, arranged as 4 by 4 to facilitate the explanation, but the invention proposed here can use larger amounts of rows and columns, where the number of rows and columns are not necessarily equal. This sweep can be expanded, with a single counter, in different ways, one of which is the following: determine a number of columns that is power of 2, and a number of rows that is also. Then the number of bits generated by these accounts is determined and concatenated, assigning a decoder to each account that has the necessary lines per column and, if applicable, row. In general, you have an X-bit account that is divided into Y and Z bits, where Y + Z = X (Y: Z = X). A decoder is used from Y to 2Y lines that is controlled by the bits called Y. Another decoder from Z to 2Z lines that is controlled by the bits called Z. The circuit would control a total of 2X LEDs that would light only one at a time. The account generated by the only decimal point in the circuit would be the Z account. Returning to figure 5, it shows a schematic diagram of a controller with 16 LEDs. In this diagram the following components are shown: A binary counter 74393 (17) that is fed by a square signal of frequency dependent on the number of LEDs (60Hz x # of LEDs or higher), in the example described here would be 960Hz (60Hz x 16). The binary counter is connected to a pair of decoders where the first of them is 74138, (18) and controls the rows, takes the most significant bits, and the second, the decoder 74138 (19) controls the columns, taking the bits less significant. The outputs of the second decoder (19) have to be inverted to control the NPN transistors as previously mentioned. The control system requires two voltages, VCC and VDD; said voltages can be obtained both from the AC network and from a DC source after being converted and regulated. As illustrated in Figure 6, the value of VCC (20) and VDD (21) may vary. VCC by definition is 5V and VDD will be set according to the model, number configuration and type of LEDs and their voltage and / or current requirements. This value may be equal to 5V for ease. If VCC is greater than or equal to VDD the schematic described in figure 6 is used. Otherwise, see figure 7 which is the complete schematic diagram with Zener diodes (22); which is used if VDD exceeds VCC (5V), and which consists in that a Zener diode must be added in each row to protect the circuit, as shown in figure 7. The value of said Zener diode (22) must be of VDD less VCC rounded to the Zener commercial value that follows it in greater magnitude and must be set in such a way as to generate a voltage drop in the direction of the base of the transistor to the output of the decoder of the row as shown in said figure .

In summary, the sweep is responsible for the selected, alternate and consecutive lighting of individual LEDs or groups of LEDs that represent a fraction of the total LEDs of the light source. To summarize, to obtain VCC and VDD, two phases called rectification (4) and CD-CD conversion (5) are required; shown in figure 2. In figure 3 only the CD-CD conversion (8) is found to obtain VCC and VDD. The rectification phase is made up of LEDs that are connected in the form of a full wave rectifier bridge Figure 8, powered by a variable voltage but the rectifier can have variants using more LEDs in the bridge as shown in Figure 9, or several bridges in parallel as figure 10, this to perform a better rectification and also take advantage of the use of rectifier LEDs as a light source of energy, resulting in low power consumption since it does not require an extra rectifier phase (CA-CA) ) to energize the LEDs and also achieve greater lighting. For the rectification stage of the circuit shown in Figure 8, a typical rectifier with a full-wave diode bridge is shown. Its objective is to rectify the voltage of the focus socket (l 10 or 220 Volts AC to 60 or 50 Hz). This rectification is done by the four LEDs identified in the figure as D I, D2, D3 and; D4; obtaining a pulsing voltage always positive. A capacitor (23) is used to convert the pulsations to a constant voltage value, which causes the output of the rectification circuit to be a CD voltage without ripple, which is passed to the CD-CD conversion stage. This variant replaces the diodes with light-emitting diodes. In the present invention, the above has two functions: the rectification of the input sine wave (1 10 or 220 Volts AC) and at the same time produces illumination, with which less LEDs can be used in the scanning stage, and thus have more energy saving The frequency of oscillation is approximately constant, since it depends only on the frequency of the socket (50 or 60 Hertz). The main objective of the CD-CD conversion stage is to reduce the DC voltage that delivers the rectifier to a voltage VDD that is useful for the network of LEDs, and which is determined according to operating parameters thereof. The basic circuit of this stage, shown in Figure 1 1, consists of a CD-CD converter, known as a chopper reducer. This circuit is composed elementally of a transistor (24), a diode (25) and an inductor (26), whose objective is to maintain a relatively constant current at the output of the circuit. The transistor (24) allows, by means of a trigger circuit, to decide what percentage of the input voltage (Vented) is transmitted to the output, which allows to vary the average output voltage as desired. Since the output voltage is a square-shaped pulsating voltage, a capacitor (27) is used to make constant Vout. For technical reasons it is required to place several of these circuits in cascade. At the output of these two stages, the voltage obtained is that required for the correct operation of the LED network. The values of the components and the number of circuits that must be cascaded for the CD-CD conversion stage is determined by the voltage parameters VDD and current required for the LED network. When the VDD voltage is not equal to that required for VCC (for example 5 volts), an integrated circuit with a commercial voltage regulator can be used.

Claims (10)

CLAIMS Having sufficiently described our invention, we consider as a novelty and therefore claim as our exclusive property, what is contained in the following clauses:

1 . An energy-saving lighting device characterized by the selective, sequential and alternating energizing of a network of lighting elements, preferably LEDs through a controller that generates decimal counts generated by one or more binary counters and one or more decoders at a frequency fixed preferably 60hz multiplied by the number of LEDs or groups of LEDs to be controlled. This network of LEDs and the controller are powered by a rectification phase and by a CD-CD conversion stage, in case the device is connected to Alternating Current (AC). In the event that the device is connected to a Direct Current source, it will only connect to the CD-CD conversion stage without the CA-CA rectification phase.

2. An energy-saving lighting device according to claim 1, characterized in that the controller for selecting and energizing the LED network preferably uses an X-bit count that is divided into Y and Z bits, where Y + Z = X (Y : Z = X). A decoder is used from Y to 2Y lines that is controlled by the bits called Y. Another decoder from Z to 2Z lines that is controlled by the bits called Z. The circuit would control a total of 2X LEDs that would light only one at a time. This addressing to the network of LEDs can be achieved in other ways, here is an efficient way to do it.

An energy-saving lighting device according to claim 1, characterized in that the arrangement in the network of LEDs has an arrangement of transistors that can perform a switching or "switching" to the LEDs. This arrangement of LEDs consists of a network with an approach similar to that of a Cartesian plane, which has "m" columns and "n" rows.

An energy saving lighting device according to claim 1 and 3 characterized in that the network of LEDs has a mesh type arrangement where each column has its own transistor (in case of using a BJT, NPN) which has its base a resistor RB, in its emitter is connected to GND or reference and in its collector is a resistor Re. Each row has its own transistor (in case of using transistors of the family BJT, PNP) which has a resistance RB at its base, its emitter connects to VDD and its collector connects a number of LEDs equal to the number of columns. Each of these LEDs is connected to the Re of the columns. You can also use transistors from other families for the same purpose, the model of the transistor is not definitive or specific.

An energy saving lighting device according to claim 1 and 3 characterized in that in the controller the decoder used to select the columns, must have its outputs denied with an inverter to perform the appropriate control over the NPN transistor.

An energy-saving lighting device according to claim 1 and 3 wherein the decoder used to select the rows, a Zener diode will be added if the voltage designated as VDD exceeds VCC, which feeds the integrated circuits. The value of said Zener diode will be VDD minus VCC to generate a voltage drop in the direction of the base of the transistor, in this case PNP, at the output of the decoder of the rows. If VDD does not exceed VCC, that Zener diode is not added.

An energy-saving lighting device according to claim 1 characterized in that in case the device operates with Alternating Current, it uses a phase of full-wave rectification replacing the normal diodes with LEDs, which makes the system have a low consumption of power in addition to the bridge rectifier would also have the function of illuminator, thus increasing the intensity of light generated by the device.

An energy saving lighting device according to claim 7, characterized in that the rectification phase is formed by the LEDs that are connected in the form of a full wave rectifier bridge, powered by a variable voltage and the rectifier can have variants using more LEDs on the bridge, or several bridge rectifiers in parallel to perform a better rectification and also take advantage of the use of LEDs as a light source of energy.

9. An energy-saving lighting device according to claim 7 and 8 characterized in that the waveform of the supply voltage signal is not only confined to the sinusoidal shape (available in most of the world's current sockets with frequencies between 50Hz and 60Hz) but the present invention is generalized to any waveform in which the full wave bridge based on light emitting diodes (LEDs) can be used for rectification.

10. An energy-saving lighting device according to all the preceding claims from 1 to 9 characterized in that among its multiple applications it can be used as a conventional focus, or as a direct current source to produce illumination.